Referencing jddarcy's 8369312: Refactor Float.toHexString() to avoid use of regex (https://github.com/openjdk/jdk/pull/27780 <https://github.com/openjdk/jdk/pull/27780 >), we can further eliminate the regex and StringBuilder in Double.toHexString to improve performance. To make my proposal easier to understand, I've prepared a draft PR: https://github.com/openjdk/jdk/pull/27811 <https://github.com/openjdk/jdk/pull/27811 > - Shaojin Wen
